Peters' anomaly - anaesthetic management.

SUMMARY
Peters' anomaly occurs as an isolated ocular abnormality, in association with other systemic abnormality or one component of a number of well-defined syndromes. We review our experience of anaesthetic management and systemic association of peters' anomaly. To the best of our knowledge there are no reports in the literature of Peters' anomaly with relevant to anaesthesia.


Introduction
Peters' anomaly was first described in 1906by a German Ophthalmologist, Dr. Alfred Peters. It is characterized by a central corneal opacity due to defect in the cornealendothelium, Descemet's membrane, and posterio r stroma. Systemic associations with Peters'anomaly include trisomy 13-15, partial deletion of chromosome arm 11q, and Norrie disease 1 . Major ophthalmologic complications in patients with Peters' anomaly include glaucoma anddeprivation amblyopia. Despite aggressive surgical and post operative care, almost 50% of patient lose all light perception, mainly because of glaucoma.

Case Series
Nine patients with Peters' anomaly, admitted for various eye procedures in our ophthalmic institute. Diagnosis was made by the ophthalmologist and paediatrician. Patient's characteristics are described in Table 1. Allchildren underwent preoperative examinations and major congenital malformations were recorded. Investigations were done as per the requirement. Children age less than three years and more than 6 months were premedicated withpromethazine syrup 2 mg.kg -1 . Anaesthetic technique was planned accordingto their clinical involvement.
Fivepatients admittedfor examination under ana-esthesia (EUA). In the operatingtable, ECG, non invasive blood pressure and oxygen saturation were established (Datex Ohmeda). General anaesthesia was induced with O 2 :N 2 O and sevoflurane 5 -8 %. Intravenous (IV) access was secured after induction. Anaesthesia was maintained with using O 2 :N 2 O:isoflurane mixture. In allchildren spontaneous respiration was maintained with a face mask attached to T -piece. Laryngeal mask airway (LMA) was inserted in two patients because of difficulty in holding mask due to mandibular hypoplasia. The procedures were completed without any complications.
Threepatients wereoperated foropticaliridectomy and one for keratoplasty.Anaesthesia was induced with inhalational agent, using O 2 :N 2 O and sevoflurane 5 -8 %. IVline was secured after induction andfentanyl was given 1-2 mcg.kg -1 for analgesia. LMA was inserted when an adequate depth of anaesthesia was achieved (MAC-LMAinsertion forsevofluranre 2.0-2.5%). Anaesthesia was maintained with O 2 :N 2 O:isoflurane mixtureand pressure-controlledventilation wasused intraoperatively by adjusting the pressure to maintain normocarbia. Muscle relaxation was achieved using atracurium(0.1mg.kg -1 ) and rectal paracetamol (40mg.kg -1 ) was inserted in allthe patients for postoperativeanalgesia. Weencountered difficultyin intubating the trachea of 1½ month old baby who was operated for iridectomy.Tracheal intubation was planned but couldn't be intubated in the first attempt due to mandibularhypoplasia andanterior larynx.Finally intubation was done after fifth attempt with stylet and BURP maneuver.
Intraoperatively ECG, non-invasive blood pressure, end-tidal carbon dioxide and oxygen saturation were monitored.At the end of surgery, neuromuscular blockade was reversedwith neostigmine(50-70mcg.kg -1 ) and glycopyrrolate (10mcg.kg -1 ). Extubationwas performed with the child fully awake. All patients were shifted to post anaesthesia recovery room for monitor-ingandoxygen wasadministered by face mask tillthey were fit to be discharged or shifted to ward.

Discussion
Anaesthetic management of Peters' anomaly varied dependingon the clinical manifestations and associated other anomalies. Anaesthetic consideration includes possibility of difficult airway, presence of congenital heart disease and other systemic anomalies. Systemic associations are described in the Table 2. Midline body structures seem tobe involved.All asso-  Most common heart disease is acyanotic heart disease with left to right shunt. In our case series, four patients had acyanotic heart disease with left to right shunt (VSD, PDA, ASD). Inhalational induction was done in allchildren usingsevoflurane as sevoflurane has been shown to preserve myocardial function better in patients with congenital heart disease (CHD) as compared with halothane 3 . In our case series there were no significanthemodynamic changesafter induction.
In Peters' anomaly airway management may be difficult in patients with significant dysmorphic facial features, especially with micrognathia andcleft lip/palate. The anterior mandibular space is reduced due to micrognathia,thus makingtracheal intubation more difficult in Peters' anomaly. In our case series, five patientshad anticipated difficult airway problems (micrognathia, cleftlip/palate, smallmouth opening, anterior larynx). We used LMA in these patients without any difficulty.The otheradded advantages of usingLMA in ophthalmic procedure are:(i) intraocular pressure and coughing arelower withthe LMAthan thetrachealtube (TT) (ii)Anaesthetic depth requirements are lower for the LMA than the TT 4 . Fibreoptic intubation should be considered in patient with limited mouth opening and cervical vertebral anomaly.Although not a significant feature of this syndrome, patients with hyper or hypo mobility joint disease may require careful positioning and padding.
Mentalretardationis common in majority of these patients and seizures have been less reported. In our case series none of the children had mental retardation and seizures. Mental retardation may limit patient cooperation,therefore sedativeand/ oranxiolytic premedication may be helpful. In 1984, van Schooneveld et al first proposed the term Peters'-plus syndrome, comprising Peters anomaly, face anomalies, clefting, short limb dwarfism, and retarted development 5 . In our case series, some patients presented withsome of these findings. However, no cases completely fulfilledthe criteria forthis syndrome. One important differential diagnosis is anterior chamber cleavagedisorder (Jungwolff back stahlsyndrome)which includes cerebellar hypoplasia, hypothyroidism, andtracheal stenosis 6 .Peters' anomaly with history of airway obstruction should always be screened for tracheal stenosis and hypothyroidism.
Preoperative echocardiography, neuroimaging studies and other diagnostic studies should be done whenever indicated. The ability to detect associated systemic anomalies in the early stage is important, because early treatment for those anomalies is essential for normaldevelopment. We have been referring such patients for examination to a paediatrician on their first visit. We feel that patients with Peters' anomaly be screened for systemic malformations and anaesthetic implication is based mainly on the presence of systemic anomalies anddifficult airway.